How fast do they sink in the soil?

[dewcon4414]

good one RB.... now that that same jar, put a lid on it barry it say 3 inches and come back in 5 years.... you may or may not be able to find it because it moves. Thats why old timers that barried their coins used various markers and still lost those jars that part of the reason we still find them. No argument that various trees are surface trees especially maples here in IN. With the thinking that coins dont move then lets add this. I grid the heck out of an area should i ever go back and hunt it again for old coins? I think most would say they would especially if they found old coins there. Whats that old thought.... you never get it all... why not? I admit your finds get slimmer and some say you missed that one on edge at 3 inches... but why did it move, different angle, change in moisture, faster sweep? If coins dont move then we will soon be waisting our time.

Dew

Dew

 

[Shambler]

Your jar experiment is what most would consider a control (inside or outside). It's not supposed to sink. BUT ----- Put 2 inches of water in it and let it evaporate in the sun every 10 days, then freeze it in the freezer for a few months, put some worms or other underground insects/larvae in it for a few monts each year, and sit it on your operating subwoofer for a day a week - THEN you'd have a real experiment. My guess is in your "thirty years", that coin would be resting on the bottom of the jar.

You can look at nearly 100 year old pictures of homesteads and parks and then go hunt them. The ground is no higher - heck you can see the same roots under trees in some of the pictures. The silver though is 7" deep. To say that every coin is a victim of backfill, mud cracks, or 7" of organic decay buildup is cooooky talk.

 

[Dancin' Dave]

Wow ... This is really a good discussion. Some of the comments made are really well thought out. A simpler way to look at this topic is to note that coins do not move dirt but dirt can move (or bury) coins. When an object dropped on the surface, it can lay there for a long time before anything happens. Usually the first thing that occurs is that it is covered by a thin layer of soil and plant debris that has eroded due to a good rain storm rain or melting snow. Dead vegetation and dust can also layer on top of it. This eventually provides a matrix for plant roots to grow, further covering the object and even pushing it deeper. As the ground freezes and drys out, voids are created that the object can slip into when conditions change due to things like a spring thaw or a summer thunder blaster.

The depth that objects are found at mostly relates to how much time has passed, the density of the soil, and the extent that they are exposed to these elements ... not so much their weight. This is why you can find a pull-tab or a piece of foil at the same depth as a quarter.

Is it spring yet?

HH
DD

 

[DirtFlipper]

I've always figured it's a combination of settling and getting covered up, churned, turned, and wormed.

But the net is that stuff ends up under the ground, and one goal I have at a site is to find out what the 'age' is and at what depth. Finding coins certainly helps, but coins often circulate for long periods of time before being lost, so even they can be somewhat iffy indicators of age vs. depth. This is one area where recovering a few more trash targets early in a hunt pays off. Pull tabs, bottle caps, and to some extent nails, are sometimes better indicators of age vs. depth since they typically are lost contemporary to when they were made/used.

Knowing the designs of the early pull tabs ("zip tabs"), and the fact that they weren't introduced until 1962 provides a fairly reliable "K-T line" equivalent for detecting in undisturbed soil. Knowing the progression of bottle caps ("crown caps") from the original cork backs through plastic sealed also helps. Whatever depth these are being found at usually indicates a need to find stuff deeper than them.

I also like to watch out for inversions - finding newer stuff deeper than older stuff (like newer tabs deeper than older ones). This may indicate a "fill and till", which could work out favorably if older stuff was brought up in the process. This type of hunt truly becomes a mixed bag, but can yield nice surprises if others thought it was "too new" and passed.

Anything on slopes may be subject to erosion or washouts, so what was once deep is now very near the surface. When I start to see older bottle caps or tabs lying on surface dirt, where the ground cover has perhaps washed away, time to slow down.

Overall though, it seems in generally undisturbed ground folks are finding Indians and Barbers at eight inches, give or take. That seems like a reasonable enough indicator to me.

HH,
DirtFlipper

 

[Dancin' Dave]

I agree with your comments DirtFlipper. The only thing I would add is the depth that coins are buried is not linear with time. I've found Indians and Barbers only an inch or two below the pull tab layer. It seems like the change in depth has a tendency to stabilize or slow after an extended period of time has passed. My guess is that this starts to happen once the coins are deeper than the plant root level.

DD

 

[UtahRich]

Hi Shambler. I will politely disagree with your statement that "the ground is no higher" in your last post.

Having used old photo's a number of times for my own hunt site research, I can't agree with your statement that there is no change in the height or level of the ground as debris, grass clippings, leaves, etc., accumulate over the days, months and years. It is a FACT that it happens. It is natural composting. It is where the topsoil that covers our farmlands, yards, forests and plains comes from. I think you should reconsider that.

As for Kooky thoughts, you are absolutely correct that not every coin that is found deep in the ground is a victim of back fill or falling into mud cracks. I didn't mean to give that impression. If that is what you gleaned from my previous posts, my writing skills need major improvement. Sorry about that. Those examples (which were brought up by others) were simply two of the infinite number of possibilities on how coins come to rest where they do.

My opinion is that the majority (not all, just the majority) of the dirt that we find above the coins we dig comes from the composting process of organic matter that creates topsoil all across this Earth. It is a natural process. It is scientific fact for whatever that is worth to you. Are there exceptions to this in some areas? Sure there are. There may be instances where the coin is disturbed by man, tree and plant roots, insects, burrowing animals, flooding, water or wind erosion and so forth, If you want to get an idea of wind erosion in the extreme, check out "Dust Bowl" in wikipedia. The wind carried away massive amounts of topsoil from one place and dumped it in another. This too, is happening all of the time, but on a much smaller scale.

As for historical photos of trees and tree roots proving that there is no such thing as composting and the accumulation of new soil on top of old, RB addressed that very well in his post above. I will add one additional thought that is inferred in his post that you might consider as you make up your own mind about all this. If you will take a look at your historical photos of the trees and their roots and then your newer photos of the same trees 50, 75, 100, 150 years later, you can't help but notice at least one obvious change; the size of the tree. Trees and their root systems are living growing entities. They are constantly growing upward and outward, both above and below the ground. Those tree roots that were on the surface in your original photos are now much larger in diameter and spread out much further away from the base. The trunk of the tree, depending on the type, will be much larger in diameter as well. What happens to the dirt that surrounds the tree roots, trunk and so forth as the tree grows. I would hypothesize that it is compacted, and pushed out away from the roots and trunk as they expand. When those trees die, they will eventually fall over, decompose and add to the new soil on top of the old; ever growing upward.



Anyway, as this discussion continues, I'm hoping that somebody can throw in their thoughts about how the winter freeze / spring thaw relates to all this.

We know that the ground expands, due to it's water content, when it freezes. It would seem logical that it would contract and settle as it thaws........... How does this expand and contract contribute to a coins movement. (I am only using 'coin' for convenience. It could be a 3 ring bullet, wedding band, musket ball, belt buckle or any other relic or jewelry item)


Thanks,

Rich (Utah)

 

[dewcon4414]

Hey rich, get yourself a jar fill it half full of wet dirt, I say wet because here in Indy thats normally what happens in the winter. Then put a coin half way down in the dirt and get a good measurement. Then put it in the freezer. Get a measurement before the freezer, after freezing, then let it thaw and get the final measurement. I wouldnt think there would be too many more veritables. I think Dave explained it pretty simply ... sounded good Dave, works for me.

Dew

 

[UtahRich]

Hi Dew,

That would make a very interesting experiment. Only problem is that right now, all of my dirt is frozen solid. I'm sure everybody east and north of Utah is having the same problem or worse. It was 16* F when I walked out to my car this morning. High today was 28*. It's been frozen for three or four weeks now. It doesn't get much better for the next week.

On the bright side, there is usually a short midwinter thaw of some sort and I'll take that opportunity to try a little testing.

On a side note, several of you mentioned that you would find copper coins with a small amount of preserved grass thatch or clippings on one side. I have used a Hole Hog to retrieve coins for most of my 25 years of detecting and have seen this type of thing hundreds of times. For those of you not familiar with a Hole Hog, it is a coin retrieving device similar to what golf course greens keepers use to cut holes for the cup. The Hole Hog is 3" wide and can take a plug 7 1/2 inches deep. My primary hunting location is the yards of old homes and homeowners do not like it when you make a mess of their yard and lawn areas. The Hole Hog provides me with an exceptionally neat and tidy way to remove targets from a lawn.

As you retrieve a target with the Hole Hog and lift the core of dirt from the ground, the core will often break at the level of the coin, leaving a portion of the core in the bottom of the hole with an impression of the coin in it. Flipping over the Hole Hog would reveal the coin stuck to the bottom of the upper portion of the core. Sometimes the coin would be staring up from the bottom of the hole.

That impression left in the bottom of the hole would oft times be lined with the remnants of grass. I only remember finding this grass lining on pennies, nickels and copper / brass trade tokens.

When I started hunting with my Explorer XS in August of 2000 I started having problems when retrieving coins with my Hole Hog. I was finding coins deeper than my Hole Hog could reach and I was finding a lot more coins that were not laying flat in relation to the surface. I didn't have much trouble with flat coins, but I was hitting a larger percentage of my targets because they weren't laying flat. I was seeing way too many surface nicks and scratches on the coins.

In the last couple years, I mostly leave the Hole Hog in the car. I have reserved it's use as a last resort for very particular home owners. I've found that I by using a Lesche digger, or similar, I can make a wider plug that allows a deeper hole that doesn't risk as much damage to a potentially valuable coin or token.


Sorry for straying off topic.

I hope all of you have a wonderful Christmas and a Happy New Year.

Rich (Utah)

 

[Bayrat76]

Soil conditions and the type of soil mean a lot on how fast coins and other stuff sinks. Soil Microorganisms, earth worms, and other stuff play a part too. I under stand that in a rockey area with a firm base coins and other objects want sink that fast. But in a sandy and well composting soil stuff will move,and sink. After all the classes I had to take for my job on microorganisms there is almost nothing that they want eat. With a good microorganisms balance to the soil things will sink and rise. Roots and other plants play a big part in this, plus people and animals walking and rooting around will move things, Ants, gophers, and Moes move coins. In a sandy conditions big buildings have deep footings some which go 90' in the ground to help stabilize sinking. It's all in how the soil in your area is made up and what lives in the soil too.

 

[Hotcz70]

A lot of good info here guys...thanks

 

[dippodigger]

I agree and this information is very useful.

 

[UtahRich]

I have a composter in the back yard that I toss grass clippings, garden trimmings and other organic stuff into. It is amazing how much organic material this thing will swallow. It takes quite a bit of organic material to get a relatively small amount of dirt.

As was mentioned in a post above, the organic breakdown process is accomplished through a number of different ways; micro organisms, insects, worms, animals and so forth. It doesn't all happen at once. It would seem that the higher the volume of decaying material the greater the amount of dirt it would be converted into over time. Thus, a well watered and nutrient rich lawn would grow more rapidly than one that is dry and lacking nutrients. This in turn would created more organic material faster that would need to compost making for a thicker layer of material in the process at any given time.

My compost pile, which has a couple feet of organic material not yet composted on the surface, is an extreme example of what is occurring on the ground of a lawn area. As you get deeper into the compost pile, the material becomes heavier and more dense.

If I were to place a coin on the top of the compost pile (and not add any additional organic material) would the coin remain 'on the surface' or would it 'sink or fall' thru the less dense material until it reached some sort of equilibrium with the surrounding dirt matrix?

Also, as I've taken thousands of lawn cores over the years with my hole hog, the average lawn around here has 1/2"-3/4" of thatch and other organic debris in the process of being decomposed on the surface. After that, the dirt is pretty consistent down several inches. The grass roots, which must contribute in some way to all of this, will typically reach from 2" to 5" inches deep, depending on how well the lawn is watered. Dry lawns will have shallower root systems, watered lawns deeper.

Is this what you see out there when you are hunting lawn areas?


Rich (Utah)

 

[rbholt80]

coins may not sink much compared to the build up of earth ontop of them but things do sink in soil.
my fathers house was build on cinder blocks as many are done in southeast texas and the house was built in 93. it was 3 feet off the ground when new but now is only 2 feet off the ground. he did bring in dirt around the house to make it look like it sank it actualy has sunk a foot. i had an old trailer on my land when i bought my land. that trailer had wheels lol redneck. but anyway after teen years i sold that junk trailer. the guy that scrapped it couldnt see the wheels and asked me if had any on it. i told him yea and went to show him. well when i got out there i couldnt see any wheels on it so we started digging and found them. the trailer had sank all the way down to the frame covering the wheels.
so things do sink in soil. maybe not as much for coins but there is sinking. i still say its mostly covering from decay and things but there has to be a small amount of sinking.

 

[Andrus(ut)]

n/t

 

[KurtB]

Tom Dankowski wrote an interesting article about the sink rate. He has a website you could probably find it on there somewhere.

Kurt

 

[Jason illinois]

I think one thing to consider is whether the place the coin lands when it is lost was compacted by footsteps, horses and wagons etc. before the coin was initially lost. I have found some coins on the surface of old trails sitting right where they dropped 100+ years before.

Then there are areas that have been trampled a little but gravity and rain and worms and roots and freezes and thaws over the years let the heavy coins sink down into the earth.
Then there are areas with 8 inch deep memorials that have never been compressed and swallow coins and suck them down into the deep abyss.

Put a coin on the surface of a cup of dirt full of worms and see if it stays on the top!

 

[UtahRich]

I google'd Dankowski's name and found his website as well as the article you referred to. Very interesting reading.

In a nutshell, Tom D planned to do some detector testing on a beach and brought a womans wedding bad with a long thread attached so it wouldn't get lost. He set it on the wet sand and prepared to begin his testing. When he looked back for the ring, it was gone. Inspecting the thread, he found that within a couple minutes, the gold ring had sunk approx. 24" until it came to a firm base beneath the sand.

From this he suggests that when beach hunting look for areas of hardpan, where heavy items would come to rest, like gold being found on bedrock.

He does some additional testing with coils of various sizes at an inland location that has been undisturbed to the best of his knowledge for over 100 yrs. He begins searching a measured area with a small coil and working his way up to an 8" and then 10.5" coil, He hunts from 3 different directions with each coil. With the two smaller coils, he finds few coins, 2 for each coil at. When he uses the large coil, he finally finds a large number of coins, mostly from the 20's, at a depth of 10-11".

He observed that the coins are layered in depth by age of coin. Deeper he goes, the older the coins become. The bigger the coils he uses, the deeper he goes. After his testing, he returns his detector to the factory for unrelated repairs and when returned, finds that it not only has it been repaired, but fine tuned as well, getting an additional 2" of depth on a dime sized target. He returns to his measured area and finds even more coins, from the late 1800's at depths of 10-13".

He surmises that the sink rate of the coins has everything to do with soil density. In application, coins and jewelry will reach a depth of equalibrium where the density of the dirt surrounding the coin is the same as that of the coin. Surface area of the object must be taken into account as well.

****************

This example makes sense to me. If we want to answer the question of "How coins come to rest where they do?", I think we have the following variables:

1. weight and shape of object
2. density of the ground on which the object is lost.
3. wind and water erosion or deposition
4. accumulation of organic material (location dependant i.e. bare dirt, grass, forest floor, etc)
5. outside forces - digging or dumping of dirt, animals, insects, roots of vegetation,

6. freeze / thaw cycle.

Anything else that should be added?


Anybody care to chime in on the freeze / thaw cycle?

Rich (Utah)

 

[SaltnPeppersPlace]

Just how important is depth? Why do objects sink at different rates? Ever hear statements like,

 

[Hobo lobo]

According to that theory pull tabs would never sink, the S.G. of alum. is about the same as soil or sand. Im sure all of us have dug pull tabs 5 or 6 inchs deep in places that are not filled or tilled. How abou ancient
cities being uncovered by archeolgist, many feet down. Did they sink and still remain intact? I think sometimes objects do sink ( like on the beach) but in many or most intances they just get covered I used to metal detect for gold nuggets in the desert and I have found them on the surface with desert varnish on the exposed side. I don't know how long it takes for the varnish to form, but its a long time. In the absent of vegatation the nugget was still on the surface, and it is 6 times as dense as sand.

 

[gitterdug]

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